Georgia has accused Russia of conspiring to overthrow President Mikheil Saakashvili in a coup after government troops staged a mutiny at a barracks near Tbilisi.

The accusations, angrily denied in Moscow, threatened to spark a new political crisis in the Caucasus nine months after the ex-Soviet neighbours went to war over the breakaway region of South Ossetia.

The alleged conspiracy began with an uprising at the Mukhrovani military base, 25 miles north-east of the capital, Tbilisi, where officers in charge of a tank battalion stationed there led their men in an apparently non-violent mutiny.

Government officials were quick to claim that the rebellion was part of a broader plot, planned with the connivance of Moscow, to seize control of the pro-western government and kill the president.

The interior ministry alleged that a series of mutinies at bases across the country had been planned but had failed because the core of the conspiracy had been thwarted before it could unfold.

The soldiers at Mukhrovani quickly surrendered after Mr Saakashvili went to the base to negotiate with the mutineers. Their commander, Col Mamuka Gorgishvili, was detained.

Col Gorgishvili had earlier released a statement to the Russian news agency, Interfax, claiming that he had launched the mutiny in protest at a confrontation between the government and the opposition, which has mounted month-long protests calling for Mr Saakashvili's resignation. He said he had no intention of moving his men out of barracks.

But in a televised address to the nation, the president said that the plot was serious, threatened constitutional order and appeared to be linked to Russia.

"The plan was to stage a large-scale mutiny in Tbilisi and to take steps against the sovereignty of Georgia," he said. "I demand from our northern neighbour that it refrain from provocations."

Others were more blunt, claiming that Moscow had planned a "full-scale military coup".

"We have information that the rebels were in direct contact with the Russians, that they were receiving orders from them, that they were receiving money from them," said Shota Utiashvili, the interior ministry's spokesman.

The accusations prompted anger in Russia, where officials called the charges "sick" and "irresponsible" and derision from Georgia's opposition, which accused Mr Saakashvili of staging a piece of "political theatre".

Even Georgian officials seemed to contradict themselves, with some who had alleged that a coup attempt was underway later claiming that the mutiny was only intended to disrupt a Nato military exercise which begins on Wednesday.

Russia has denounced the exercise, claiming that it amounts to a reward for Georgian "aggression" during last year's war. Sergei Lavrov, the Russian foreign minister, will boycott talks with Nato this month in retaliation for the exercises and for the alliance's decision to expel two Russian diplomats accredited to its Brussels headquarters after accusing them of espionage.

Relations between Tbilisi and Moscow are likely to sour further after Georgia released video footage, broadcast on state television, which allegedly showed a former defence ministry official trying to recruit undercover spies to join Tuesday's plot.

The man is shown describing plans to seize control of the government by leading a convoy of 200 military vehicles, backed by 5,000 Russian troops, into Tbilisi.

Some commentators said that the allegations seemed overblown, pointing out that there had been two earlier mutinies, over pay, at the Mukhrovani barracks in 2001 and 2004.